Single step measurement of optical transmitters Henry factor using sinusoidal optical phase modulations

Area of Science:

• Optoelectronics
• Semiconductor Lasers
• Optical Modulators

Background:

• The Henry factor, crucial for laser dynamics, is challenging to measure over wide optical bandwidths.
• Existing methods for determining the linewidth enhancement factor (LEF) can be complex and time-consuming.

Purpose of the Study:

• To develop and validate a rapid, single-step technique for measuring the Henry factor over large optical bandwidths.
• To apply this method to directly modulated lasers and electro-absorption modulators (EAMs).

Main Methods:

• Utilized a sinusoidal phase modulation method for Henry factor measurement.
• Performed measurements in a single step without optical filtering.
• Applied the technique to a directly modulated Fabry-Perot laser and an EAM.

Main Results:

• Successfully measured the linewidth enhancement factor (LEF) for 14 longitudinal modes of a Fabry-Perot laser.
• Determined the α-factor for an EAM over a 15 nm optical bandwidth.
• Achieved excellent agreement with the established fiber transfer function method.

Conclusions:

• The sinusoidal phase modulation method offers a fast and effective way to measure the Henry factor across broad optical bandwidths.
• This technique is versatile, applicable to both directly modulated lasers and EAMs.
• The results demonstrate high accuracy and good correlation with conventional methods.